FIG. 1A illustrates a prior art crawler 190 having a ripper assembly 195 in the rear. The ripper assembly includes hydraulic cylinders 197 and 198 that control the height and pitch of the ripper assembly. The ripper assembly 195 is also shown with a small length shank 120 installed therein. Shanks of small lengths, as shown in FIG. 1A are typically used for construction jobs.
FIG. 1B illustrates the ripper assembly 195 in more detail with shank 120 installed therein. Also shown in FIG. 1B is an extended length shank 125. In general, a crawler 190 uses the extended shank 125 for farming purposes for planting or re-planting an orchard, e.g., to rip a groove several feet deep in a process called deep ripping, also called subsoiling. A pocket 130 within the ripper assembly 195 of the crawler (a large tractor with tracks) is used to hold the shank 125 vertically with a portion of the shank disposed under ground. The pocket 130 is a slot made through the pocket beam 135. The crawler moves forward slowly while holding the shank 125 and thereby rips a groove in the dirt.
However, crawlers are not equipped with a mechanism to install the shank 125 into the pocket 130. The problem with installing the extended length shank 125 is that the height of the shank 125 when positioned vertically, as shown in FIG. 1B, is much higher than the height that the ripper assembly 195 can raise the pocket 130. Installing an extended length shank 125 into the crawler's pocket 130 is a lengthy, manual, and very dangerous process involving several workers. Depending on the conditions in the field, the shank installation time may vary considerably making the process of shank installation very unpredictable. Also, the shank 125 may weigh thousands of pounds (e.g., 3,500 pounds) and installing the shank 125 into the crawler's pocket portion 130 may result in serious bodily injury if not done properly.
As stated above, the height of the shank 125 when positioned vertically, as shown in FIG. 1B, is much higher than the height that the ripper assembly 195 can raise the pocket 130. Therefore, when the ripper assembly 195 is fully raised, the shank 125 is taller than the height of the bottom of the pocket 130. Therefore, it is not possible to install the shank within the pocket, unless the shank is somehow depressed into the ground or an uneven surface is located, e.g., a stair-stepped surface is present in the field. The problem of shank installation is exacerbated if the crawler needs to be transported often because the crawler cannot be transported with the extended length shank installed due to state law weight restrictions on transport low beds. In other words, when ripping services are contracted to farmers, etc., the crawler and shank need to be transported from job site to job site. Because the crawler cannot be transported with the shank installed, each time the crawler needs to be re-located, the extended length shank needs to be removed, transported on a separate smaller trailer and re-installed. This is typically not a problem with respect to the shorter shank of FIG. 1A because the shorter shank 120 can be left installed during transportation. Furthermore, construction jobs typically do not involve so much travel because the job lengths are longer when compared to ripping.
Today, there are several ways in which the extended length shank 125 can be depressed into the ground to lower its height for installation, but these methods are manual, time consuming, dangerous and often rely too heavily on conditions in the field which are unpredictable. In one method, the shank is removed from a trailer using the ripper assembly of the crawler. The shank is tied to the ripper assembly with two chains with the pointed end of the shank positioned lower and downward. The shank is then dropped so that its weight drives the pointed end in to the ground and the shank is left at an angle to the ground (not perpendicular) hoping that when the chains are removed it will stay in this position. The crawler then uses one of its tracks to climb up the length shank, thereby pushing it deeper into the ground. When it has been pushed enough, the crawler repositions itself in front of the top part of the shank and backs into it. Using the ripper beam touching the top of the shank which is at an approximate 45 degrees, the crawler applies pressure hydraulically as it moves backwards, causing the shank to go further down and more vertical, though not at the perfect angle. If process was successful at driving the shank deep enough, then the tractor will back into the shank to straighten it up. At this point the ripper assembly can be properly positioned over the top of the shank and inserted. This process is very labor intensive, dangerous, unpredictable and is rarely successful, depending on the conditions of the ground, etc. Moreover, if the shank is unable to be depressed into the ground a sufficient amount, then objects can be placed under the crawler's tracks to raise the ripper assembly by backing onto to them so that the pocket can be positioned over the shank's top to hammer and/or align the shank for proper installation. However, because of the weight of the tractor (approximately 115 tons), any objects used to elevate the machine are lost into the ground. This is usually only tried if it is believed that the ground is hard enough to withstand its weight.
Another method for installing the shank involves using a chain with a loop secured through the lowest hole in the shank and to a portion of the ripper assembly. The ripper assembly is then raised to raise the shank vertically. The bottom of the shank is then driven into the ground by lowering the ripper assembly and applying pressure to the chain loop pulling downward on the shank thereby depressing it into the ground. Again, much like the first method described above, this second method is also labor intensive, very dangerous (as the chain can give way) and is unpredictable.
Accordingly, the problem with installing an extended length shank within the ripper assembly of a crawler lies in the fact that the shank is taller in height than ripper assembly can raise the pocket. The conventional methods of installing a shank within the ripper assembly of a crawler are manual, time consuming, unpredictable (based on conditions in the field) and involve substantial risk of injury.